have you? or do you?

[euncu]

You haven't got the faintest idea, do you?
You haven't got the faintest idea, have you?

If I was to build a sentence like the ones above, I'd normally say the first one, but when I think over it I can't decide, it's like fifty -fifty, so what would be the correct answer?

Thanks for your answers in advance.

[riquecohen]

You haven't got the faintest idea, do you?Incorrect tag.
You haven't got the faintest idea, have you?

If I was to build a sentence like the ones above, I'd normally say the first one, but when I think over it I can't decide, it's like fifty -fifty, so what would be the correct answer?

Thanks for your answers in advance.

Only the second one is correct. You could modify the first one to read "You don't have the faintest idea, do you?